Is differential expression of p16INK4a based on the classification of uterine smooth muscle tumors associated with a different prognosis? A meta-analysis

We conducted a meta-analysis to examine p16INK4a expression in uterine smooth muscle tumors (USMTs). Although the prognostic value of tumor suppressor p16INK4a has been elucidated in a variety of cancers and precancerous lesions, its role in USMTs is not well established. We searched PubMed, Web of Science, and Embase for publication son p16INK4a expression in USMTs. Strict inclusion and exclusion criteria were imposed. Risk ratios (RRs) with 95% confidence intervals (95%CIs) were calculated to assess the strength of association. Publication bias was estimated using funnel plots and the Egger's regression test. Twelve eligible studies comprising 661 patients were included. Compared with leiomyoma (LM), the figures for the strength of association were as follows: LM variants (RR = 1.53, 95%CI = 1.03-2.27, P = 0.036, random effect); leiomyosarcoma (LMS) (RR = 3.20, 95%CI = 1.68-6.12, P < 0.001, random effect); and smooth muscle tumors of uncertain malignant potential (STUMP) (RR = 2.90, 95%CI = 1.17-7.21, P = 0.022, random effect). p16INK4a expression was significantly higher in LMS than in LM variants (RR = 3.74, 95%CI = 1.96-7.13, P < 0.001, random effect) or STUMP (RR = 1.67, 95%CI = 1.26-2.23, P < 0.001, fixed effect). There was a significant correlation between overexpressed p16INK4a and recurrence rates of USMTs (RR = 1.85, 95%CI = 1.11-3.10, P = 0.019, fixed effect). p16INK4a over expression is a potential biomarker for diagnosing problematic USMTs and it might indicate a worse prognosis. However, there is currently insufficient evidence to assess the prognostic value of p16INK4a in USMTs.